1. Field of the Invention
The invention concerns a multi-phase electric machine as well as a production process for such a machine.
2. Description of the Prior Art
In the production of multi-phase electric machines which are operated at high currents and voltages, the insulation of intersecting conductor lanes requires increased manufacturing expenditures. In order to attain high efficiency and power densities, the proportion of the conductor in relation to the groove volume should be as large as possible and the proportion of the conductor length in the winding overhang should be as small as possible.
U.S. Pat. No. 4,398,112 describes a layered winding for disk armatures and linear motors in which stamped conductor layers are inserted into the grooves from the air gap in direction of the groove depth. This results in very short lengths of all conductor lanes in the winding as described in said patent document, however, because all conductor lengths of different phases have different distances to the air gap, the groove volume is completely utilized only in single-phase machines. Single-phase machines, however, show strong variations of torque. In two-phase machines with windings in accordance with the said United States patent document the utilization factor of the grooves would already drop to 50%, and in three-phase machines to 33%.
The invention is based on the objective to advance the development of a multi-phase electric machine and a manufacturing process of this machine in such a manner that with low manufacturing expenditures high efficiency and power densities with concurrent low ohmic losses are achieved, as well as material-saving, easily automated and, therefore, cost-effective production is made possible.